let inpt = readLine()!.split(separator: " ").map({Int($0)!})

let totalMasu = inpt[0] * inpt[1]
var lose = totalMasu % inpt[2]
if(lose == 0) {
    lose = inpt[2]
}
if(lose == inpt[3]) {
    print("YES")
} else {
    print("NO")
}